DO NOT RUN THE CAR, DUMP OIL ASAP.
Since the car already had severe oil contamination, dump the oil and flush the cooler as quickly as possible. Also, dump the coolant to prevent further contamination. I advise starting the car and running it for 10 seconds after putting in some fresh oil just to flush off bearings/surfaces and prevent any possible corrosion. This is not long enough to overheat anything w/o coolant, but DONT run it longer.
After the heads & gaskets are R&R'd, dump the oil again, change the filter, and remove the oil pan as it may have coolant puddled at the bottom of it. Reinstall and refill with fresh oil, and you should be good to go.
If you need any help with the heads or any parts to repair, let us know.